Papers

Cold related mortalities and protection against cold in Yakutsk, eastern Siberia: observation and interview study

G C Donaldson, senior research associate, ^a S P Ermakov, principal researcher, ^b Y M Komarov, director general, ^b C P McDonald, director, ^c W R Keatinge, emeritus professor of physiology. ^a

^a Department of Physiology, Basic Medical Sciences, Queen Mary and Westfield College, University of London, London E1 4NS, ^b Public Health Research Institute, Russian Ministry of Health, Moscow 127254, Russia, ^c McDonald Research, Peckwater, Camberley, Surrey GU15 2LY

Correspondence to: Professor Keatinge w.r.keatinge{at}qmw.ac.uk

Objective To assess how effectively measures adopted in extreme cold in Yakutsk control winter mortality.
Design Interviews to assess outdoor clothing and measure indoor temperatures; regressions of these and of delayed cause-specific mortalities on temperature.
Setting Yakutsk, east Siberia, Russia.
Subjects: All people aged 50-59 and 65-74 years living within 400 km of Yakutsk during 1989-95 and sample of 1002 men and women who agreed to be interviewed.
Main outcome measures Daily mortality from all causes and from ischaemic heart, cerebrovascular, and respiratory disease.
Results Mean temperature for October-March 1989-95 was 26.6°C. At 10.2°C people wore 3.30 (95% confidence interval 3.08 to 3.53) layers of clothing outdoors, increasing to 4.39 (4.13 to 4.66; P<0.0001) layers at 20°C. Thick coats, often of fur, replaced anoraks as temperature fell to 48.2°C. 82% of people went out each day when temperatures were 10.2°C to 20°C, but below 20°C the proportion fell steadily to 44% (35% to 53%) at 48.2°C (P<0.001), and overall shivering outdoors did not increase. Living room temperature was 17.9 (17.2 to 18.5)°C at 10.2°C outdoors, 19.6 (18.8 to 20.4)°C at 20°C, and 19.1 (18.6 to 19.6)°C at 48.2°C. Mortality from all causes and from ischaemic heart and respiratory disease was unaffected by the fall in temperature. Mortality from respiratory disease (daily deaths per million) rose from 4.7 (4.3 to 5.1) to 5.1 (4.4 to 5.7) (P=0.03), but this was offset by a fall in deaths from injury.
Conclusions People in Yakutsk wore very warm clothing, and in extremely cold weather stayed indoors in warm housing, preventing the increases in mortality seen in winter in milder regions of the world. Only respiratory mortality rose, perhaps because of breathing cold air.